Defected army soldiers shout slogans with anti-government protesters demanding the ouster of Yemen's President Ali Abdullah Saleh, during a march calling for the release of prisoners, in Sanaa October 30, 2011. REUTERS/Louafi Larbi

Residents said they believed at least one shell had hit the al-Daylami base which is adjacent to Sanaa International Airport.

“The airport was closed as a precautionary measure,” one government official told Reuters. Flights were diverted to Aden airport in the south of the Arabian Peninsula country.

Yemen’s capital has seen weeks of fighting between troops loyal to President Abdullah Saleh and tribesmen who back protesters demanding an end to of his 33-year rule. Tribesmen in areas outside the capital have complained of months of attacks by the air force against their towns.

Tribal sources said earlier Sunday that four people, including three children, were killed overnight when troops shelled the tribesmen’s region north of the capital, hitting a petrol station.

Thirteen others were wounded in the attack in the Arhab area, some 40 km (25 miles) from Sanaa.

In the city of Taiz, south of Sanaa, a doctor said one civilian was shot dead and two were wounded by government forces who fired at a car. The incident occurred in a district where there have been clashes between government forces and pro-opposition tribesmen.

Months of anti-government protests have divided impoverished Yemen, pushing the Arabian Peninsula country to the verge of civil war and a humanitarian crisis.

Anti-government protesters demanding the ouster of Yemen's President Ali Abdullah Saleh, shout slogans during a march calling for the release of prisoners, in Sanaa October 30, 2011. REUTERS/Louafi Larbi

Neighboring oil giant Saudi Arabia and the international community fear growing lawlessness in Yemen is giving al Qaeda’s regional wing scope to plan and potentially launch attacks in the region and beyond.

The ruling party is likely to name Saleh’s deputy as its presidential candidate if a transfer of power is carried out under a Gulf-brokered power transition plan, Deputy Information Minister Abdu al-Janadi said Sunday.

Anti-government protesters demanding the ouster of Yemen's President Ali Abdullah Saleh, shout slogans during a march calling for the release of prisoners, in Sanaa October 30, 2011. REUTERS/Louafi Larbi

“The General People’s Congress intends to announce Vice President Abd-Rabbu Mansour Hadi as its candidate in the presidential election in the coming period,” Janadi told reporters.

The U.N. Security Council issued a resolution on October 21 deploring the fighting and calling on Saleh to leave office in line with the transition plan.

Saleh has dug his heels in, surviving an assassination attempt and three times agreeing to sign the Gulf plan only to back out at the last minute.

Violence has showed no sign of easing.

In the southern port city of Aden, one soldier was killed and two wounded by a roadside bomb targeting their patrol on Sunday, a security official said. Islamist militants had probably planted it, the official said.

Soldiers, security officials and tribesmen fighting militants are frequently attacked in the country’s south, where government control has been weakened by political upheaval.

Reporting by Mohamed Sudam and Mohammed Ghobari in Sanaa and Mohammed Mukhashaf in Aden; Writing by Isabel Coles and Firouz Sedarat; Editing by Jon Hemming